A hydraulic excavator which is a representative example of construction machinery is equipped with a machine body configured by a base carrier and an upper turning body mounted on the base carrier, and a work arm device installed on the upper turning body. The cab where a driver boards is in general positioned on the left front part of the upper turning body, hence the driver can visually recognize a comparatively wide range about the front of the machine body and the left side of the machine body. On the other hand, the driver can hardly visually recognize the back of the machine body and the right side of the machine body. Because of this, a hydraulic excavator in recent years is equipped with a rear monitor camera that films the rear of the machine body in the rear of the machine body and also, a right-side monitor camera on the right side of the machine body that films the right side of the machine body and there exists one that camera images filmed by each monitor camera are displayed in the monitor inside the cab.
Thereby the driver can confirm safety through the monitor if there are obstacles or workers in the rear of the machine body or on the right side of the machine body. Moreover, as to the monitor display of camera images, in addition to those that are displayed with each camera image lined up side by side, there are those that display on the monitor the synthetic bird's eye view image that has bird's eye view of the surrounding of the machine body from above the machine body by synthesizing each camera image. (for instance, refer to Japanese Unexamined Patent Application 2012-74929).
Regarding the construction machinery in which the images of the surrounding of the machine body (particularly synthetic bird's eye view image) it has become a challenge to enable obstacles and other workers to be surely recognized by the drivers from monitor camera images. To solve this challenge, one can consider to make the camera images on the monitor to be larger using a larger monitor than conventional ones. However, since the monitor in a cab is positioned in front of the driver seat, if the monitor is made larger, a concern is that the frontal visibility of the driver deteriorates, hence there is a limit in making the monitor larger.
On the other hand, in the published unexamined Japanese application is disclosed a technology in which among the synthetic bird's eye view images, an optional area only is expanded and displayed on the monitor. However, the driver cannot recognize from the expanded display where only the optional area is expanded whether or not obstacles or other workers exist in the other areas. Moreover, to expand display or cancel the expanded display, it requires that the driver operate the monitor manually, hence every time the driver expands display or cancels the expanded display, the driver has to remove his hands from the operating lever, hence it is inferior in workability.
An object the present disclosure in view of the problems described above is to provide construction machinery that does not make the monitor larger, but in which the driver can certainly recognize whether or not obstacles or other workers exist in all areas surrounding the machine body.